The invention relates to a device for die-cutting a stack of sheet-like materials, in particular a device for die-cutting a stack of labels. According to the type of device described, a stack is pressed into the die-cutter blade by a relative motion of the punching ram and a hollow cylindrical die-cutter blade. As a general rule, the die-cutter blade remains motionless during the actual die-cutting process while the punching ram presses the stack into the die-cutter blade.
A device of the aforementioned type is described in WO 96/12593. The essence of the die-cutting device described therein is that it provides an additional counter-pressure ram which serves the purpose of moving the punched stack back out of the die-cutter blade against the direction of thrust.
The object of the present invention is to produce a die-cutting device that is very compactly built as a consequence of a particular arrangement and storage of the die-cutter blade in the direction of relative motion of the punching ram and die-cutter blade.
The invention proposes a device for die-cutting a stack of sheet-like material as defined in claim 1. The essence of this device is that the die-cutter blade is adjustably held in a frame which can be slid into a receiving apparatus perpendicular to the relative direction of motion of the punching ram and the die-cutter blade and which can be fixed in a centered position, whereby the receiving apparatus is mounted in a punch platen and is adjustable relative to it. The frame that accommodates the die-cutter blade is therefore not tilted into the receiving apparatus, which would necessitate a relatively large amount of space between the punching ram and the punch platen. Rather, the device is built very compactly since the frame can be positioned in the narrowest space between the punching ram and the punch platen, in that said frame is instead slid into the receiving apparatus, indeed perpendicular to the relative direction of motion of punching ram and die-cutter blade. There the frame can be fixed in centered position, wherewith a pre-adjustment of the frame relative to the punch platen is achieved. The frame, and consequently the die-cutter blade, can be further adjusted inasmuch as the receiving apparatus is adjustable within the punch platen.
Advantageous arrangements of the device according to the present invention are described in the dependent claims:
The frame can be introduced into the receiving apparatus in particularly simple fashion if the latter exhibits two gibs arranged in parallel, between which the frame can be slid. The frame itself is preferentially adjustable in a plane parallel to the punch platen, particularly in the directions of two main axes that are essentially perpendicular to one another; and is also tiltable in said plane. In order that the frame can follow the operational motion of the receiving apparatus on center, said frame is provided with, for example, a groove which essentially runs in the direction of one main axis, into which groove a centering bolt that is primarily adjustable in the direction of the other main axis is set, and which bolt in particular is mounted in the punch platen. It is advantageous for the receiving apparatus and/or the centering bolt to be adjustable via motors, whereby the adjustment preferentially occurs in synchrony. Servomotors are particularly worth considering as adjustment drives. In particular, a clamping element is provided to lock the frame in the adjusted position within the receiving apparatus. This fixation and/or the fixation of the frame in the centering bolt is preferentially pneumatically achieved.
The aforementioned device designs ensure that the die-cutter blade, as held in the frame and introduced into the device, can be oriented in defined fashion relative to the punching ram directed toward the stack, particularly in a plane perpendicular to the relative direction of motion of the punching ram and the die-cutter blade, in each case with respect to both translational and rotational aspects.
A further advantageous arrangement of the device concerns itself with the pre-adjustment of the die-cutter blade in the frame. Essential to this device is that the frame is provided with clamping elements for fixing the die-cutter blade in place, which elements are mounted within the frame and are adjustable and lockable relative to it, as well as with an adjusting element for aligned orientation of at least one orientation edge of the adjusting element with a section of the knife edge of the die-cutter blade prior to fixation of the adjusted clamping elements.
As such, it is not necessary to fix the die-cutter blade by feel, but rather this occurs by means of a separate adjusting element. It is sufficient to establish one, in particular straight, section of the knife edge of the die-cutter blade as the relational parameter to be brought in line with the orientation edge of the adjusting element. This adjusting element is positioned on a defined portion of the frame such that aligned orientation of the orientation edge of the adjusting element and the section of knife edge of the die-cutter blade ensures exactly adjusted positioning of the cutting blade relative to the frame. The lateral orientation of the die-cutter blade relative to the frame can be accomplished in simple fashion via central markings placed onto the die-cutter blade on the one hand and onto the frame on the other, which are likewise to be brought into aligned agreement. The adjusting element may be arranged in various styles and manners. The adjusting element is of particularly simple construction when it is formed as an adjusting ruler. This rod-shaped element is placed on the frame in defined fashion and the orientation of the die-cutter blade occurs along one orientation edge of the adjusting ruler. The adjusting ruler is preferentially located a short distance behind the die-cutter blade, relative to the leading knife edge of the die-cutter blade. It is also conceivable to not only orient the die-cutter blade along one section of the knife edge, but rather along the entire knife edge. This can be accomplished in a simple manner if the adjusting element is designed as an adjusting sheet parallel to the peripheral knife edge of the die-cutter blade and provided with an opening corresponding to the cross-sectional opening of the die-cutter blade in the area of the knife edge. The adjusting sheet is located in front of the die-cutter blade relative to the leading knife edge of the die-cutter blade, for example, and is indeed oriented to the frame. The die-cutter blade is then positioned so that its peripheral knife edge coincides with the contour of the aperture of the opening in the sheet. This arrangement considerably simplifies pre-adjustment of the die-cutter blade in the frame, such that only minorxe2x80x94if anyxe2x80x94positional corrections of the die-cutter blade and/or frame with respect to the punching ram and the stack to be punched are necessary upon placement of the frame in the die-cutting device.
A further development concerns itself with the particular fixation of the die-cutter blade in the frame. In this context, it is essential that clamping elements, mounted in the frame and adjustable and lockable relative to it, are provided for fixation of the die-cutter blade. The frame exhibits a frame portion and a primary clamping beam that can be slid and locked within the frame portion, whereby the die-cutter blade is held in the primary clamping beam and in the frame portion, in a section of the frame portion that is arranged in parallel to the primary clamping beam. A secondary clamping beam, which can be slid and locked within the frame portion, is arranged in parallel to the primary clamping beam. Finally, clamping agents for clamping the primary and secondary clamping beams are provided in such a manner that the primary clamping beam can be tensioned against the die-cutter blade.
The frame portion and the primary clamping beam are thus charged with accommodating the clamping elements for fixation of the die-cutter blade. These clamping elements, which are, in particular, formed as clamping shoes, fix the die-cutter on sides of the die-cutter blade facing away from one another, such that the clamping elements of the primary clamping beam, under the influence of the clamping agents of the secondary clamping beam, press the die-cutter blade into the clamping elements of the frame. Once the clamping elements for the die-cutter blade have been brought largely into position and pre-tensioned, and the slideably frame-mounted primary clamping beam is also held relatively firmlyxe2x80x94however so that it can still be slidxe2x80x94within the frame, the similarly slideable secondary clamping beam is positioned near the primary clamping beam and firmly tightened. By adjusting the clamping agents that contact the primary clamping beam, the die-cutter blade is firmly fixed between the clamping elements as a consequence of the primary clamping beam""s slight relocation. The firm connection is then established between the primary clamping beam and the frame, wherewith the die-cutter blade is held particularly firmly to the frame.
The frame is preferentially of closed construction and consequently torsion-resistant. The connection between the primary and/or secondary clamping beam and the frame portion can be achieved via form or friction fit. According to a particular design, it is foreseen that the primary and/or secondary clamping beam can be connected to the frame portion in form-fitting fashion along wedge-shaped support sections of the frame portion, whereby the wedge of the respective support section thickens in the direction away from the die-cutter blade. It is ensured as a result of these wedge-shaped support sections that the connection of die-cutter blade and frame will not be loosened during operation. The corresponding applies to the connection of clamping elements and clamping beam and/or frame, if the clamping elements are provided with corresponding wedge-shaped support sections as well.
A further design concerns itself with the particular seating of the frame upon the punch platen and the direct introduction of punching forces from the die-cutter blade to the punch platen via those frame areas associated with the die-cutter blade. The die-cutter blade is held adjustably in the frame, which is held in the receiving apparatus that is connected to the punch platen. The receiving plate exhibits the two gibs arranged in parallel, between which the frame is held. The frame exhibits a frame portion and at least one adjustable clamping beam within the frame portion for fixation of the die-cutter blade. The clamping beam rests upon the punch platen in the vicinity of the beam""s ends; moreover, the leg of the frame portion which serves to receive the die-cutter blade rests upon the punch platen. The section of the frame portion facing away from this section of the frame portion is arranged at a distance from the punch platen. Introduction of punching forces occurs via the frame portion in the area of that section of the frame portion which serves to accommodate the die-cutter blade; moreover via the clamping beam which is adjustable within the frame and which is located in the immediate vicinity of the die-cutter blade.
Depending on the size of die-cutter blade used, accommodation of the mounting of the die-cutter blade is accomplished by sliding the clamping beam, which thus ensures that the punching forces are always introduced into the punch platen in the immediate vicinity of the die-cutter blade. Therefore, in no case does the introduction of force occur in the area of that section of the frame portion that is directed away from the die-cutter blade.
According to an advantageous further development, an additional clamping element is provided which works upon the section of the frame portion facing away from the die-cutter blade, indeed in such manner that the frame portion is pressed against that gib which is located in the area of the die-cutter blade.
The die-cutting device according to the present invention may be designed differently with due regard to the features of the generic terms of the patent claims. In the sense of the publication WO 96/12593 as discussed, it is not necessary for a counter-pressure ram that generates counter-pressure on the stack to be functioning within the die-cutter blade. As a general rule, so-called xe2x80x9cpress-through punchingxe2x80x9d will be employed, in which a stack of pre-cut labels, particularly rectangular labels, is pressed through the die-cutter blade in a single stroke. The die-cut labels are automatically pushed through the die-cutter blade by the subsequent stack.
Further features of the invention are presented in the dependent claims, the description of the figures and in the figures themselves. It is noted that all individual features and all combinations of individual features are essential to the invention.